Sophie Payne, described as a ‘warm, bright and creative’ young woman, died in July 2017.

A young woman with mental health problems killed herself after a series of major errors by the NHS trust that was looking after her, a jury at an inquest into her death has found.

It issued a scathing assessment of the care received by Sophie Payne, 22, a “warm, bright and creative” woman who died in July 2017 in the Rose ward of Queen Mary hospital in Roehampton, south-west London.

Campaigners claim the inadequacies revealed in evidence at the inquest are part of a “repeated pattern of failure” in the care highly vulnerable women receive from NHS mental services.

The jury found that five key mistakes by staff in the mental health unit contributed to the death of Payne, who was found unresponsive at 8.45pm on 27 July last year.

The jury highlighted how, despite Payne apparently trying to take her own life earlier that day, staff did not remove from her room an item she had used in that suicide attempt and went on to use to kill herself that evening.

“[The item] not being removed from Sophie’s room was a contributing factor or cause of Sophie’s death,” the jury said in a seven-page record of the inquest at Westminster coroner’s court in central London.

The jury argued the item should also have been removed because Payne had used it in four previous apparent suicide bids during her 24 days in the unit. Staff did not file an incident report about any of those four episodes, despite their seriousness and Payne’s persistent attempts to harm herself.

The jury said: “There were failing[s] in incident reporting which contributed to Sophie’s death. There were four incidents in which [the item] was found ... in Sophie’s mouth. No incident report was generated.

“[The item in her] mouth posed a ‘significant risk’, yet on four occasions [was] not reported to risk assessment.”

The jury said this led to a failure in risk assessment that separately contributed to Payne’s death.

It also found that her care plan – a document spelling out her treatment – was not updated properly after the apparent suicide attempts, a breach of the guidelines drawn up by the South West London and St George’s mental health NHS trust (SWLSTG), which runs the hospital.

The jury said the trust’s failure to hold a multi-professional review meeting after Payne’s persistent self-harm was the fifth mistake that contributed to her death.

Payne, a former youth worker who planned to go to university, suffered from post-traumatic stress disorder, bipolar disorder and emotionally unstable personality disorder. She had first been treated for mental health problems as a teenager after being sexually assaulted.

Mike Payne, her father, accused staff on Rose ward of being “complacent” in their care and not learning from his daughter’s first apparent suicide on the day she died.

“In her last four years she spent many periods in and out of different acute psychiatric wards. In our experience the level of care she received during her final admission on Rose ward was by far the most inadequate,” he said. “Her care plan was non-existent. Less than 10% of self-harm incidents were reported and her overall care smacked of complacency.”

Deborah Coles, the director of the charity Inquest, which supported Payne’s family, said: “We are increasingly concerned about the repeated patterns of failure of vulnerable women like Sophie in secure mental health care. All the warning signs were there but yet again she was failed by the very systems that were meant to keep her safe.”

Merry Varney, the family’s lawyer, said the jury’s findings had been “damning”. A nursing expert found that 42 incidents of self-harm or attempted suicide by Payne were not recorded, she said.

SWLSTG said it fully accepted the findings by the coroner and jury. “We extend our deepest sympathies and apologies to the family and friends of Sophie Payne at this deeply distressing time,” a spokesperson said.

It has begun implementing recommendations made by an independent investigation into Payne’s death that was led by an outside consultant psychiatrist.

“Over the last 11 months we have ... made significant improvements in a number of areas including in the quality and consistency of incident reporting, the process of escalating concerns, greater integration of risk assessments and care planning,” it said. “Our dedicated nurses and clinical staff that looked after Sophie throughout her illness are extremely saddened by her death.”

• In the UK, the Samaritans can be contacted on 116 123. In the US, the National Suicide Prevention Hotline is 1-800-273-8255. In Australia, the crisis support service Lifeline is on 13 11 14. Hotlines in other countries can be found here.